Electric circuit breaker



July 13', 1948' B. E. sPlRo ETAL 2,445,190

ELECTRIC CIRCUIT BREAKER Filed Dec. 20,. 1944 2 sheets-sheet 1 m, l f lllllllllllllllllml Y "I, f/

A? f5 F'g f6 by @M4 T hen Attorney.

July 13, 1948. B, E, SPIR() AL 2,445,190

ELECTRIC CIRCUIT BREAKER Filed Deo. 20, 1944 2 Sheets-Sheet 2Inventor-s: Benjamin lpir-og Faiph J.Basker-ville Then Attorneg.

Patented July 13, 1294s ELECTRIC CIRCUIT BREAKEB.

Benjamin E. Spiro, Philadelphia, and Ralph J. Baskerville, Merwood Park,Pa., assignors to General Electric New York Company, a corporation ofApplication December 20, 1944, Serial No. 568,983

Our invention relates to electric circuit breakers and more particularlyto electric air circuit breakers of the type disclosed and claimed inLinde Patent 2,293,513, granted -August 18, 1942, and assigned to thesame assignee as the present application. Specically, our invention isan immovement on a circuit breaker of the type disclosed in Linde Patent2,335,088, granted November 23, 1943, and also assigned to the sameassignee as the present application.

Air circuit breakers of the type disclosed in the above-mentioned Lindepatents have been used very extensively within the past several years..These circuit breakers. employ an arc chute of inorganic material, whicharc chute is closely adjacent the contacts of the circuit breakerbetween which the arc is drawn. Our inventionis particularly concernedwith the construction of the arc chute and supporting means thereforwhich are simple and compact and which permit ready accessibility to thecontacts of the circuit breaker.

It is an ,object of our invention to provide an arc chute for anelectric circuit breaker which is simple, compact, emcient in operation,and which is readily removable to permit inspection of the contacts ofthe associated circuit breaker.

It is anotherl object of our invention to provide a new and improved arcchute including supporting means therefor for an electric circuitbreaker.

Further objects and advantages of our inventionl will become apparent asthe following description proceeds and the features of novelty whichcharacterize our invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification.

For a better understanding of our invention, reference may be had to theaccompanying drawings in which Fig. 1 is an elevational view of anelectric circuit breaker embodying our invention with 'certain portionsbroken away; Fig. 2 is a sectional view of the arc chute only, taken online 2`2 of Fig. l; Fig. 3 is an exploded view of the arc chute of Fig.1 to illustrate the construction of the arc chute, and Fig. '4 is asectional view taken online 4-4 of Fig. 3 assuming an assembled arcchute in Fig. 3.

Referring now to the drawings, there is illustrated an electric circuitbreaker in some respects quite similar to the electricl circuit breakerdis- 3 Claims. (Cl. 20D-JM) tacts 2 and arcing contacts I andcooperating movable current carrying contact 4 and movable arcingcontact 5. Movable contacts l and l are supported on an arm B which ispivotally mounted at I to one end of a circuit breaker conductor vstud48. The relatively stationary contacts 2 and 9 serve as plug typedisconnect contacts for the circuit breaker unit and when they areconnected to a live power circuit relative separation of the contactswill cause an arc to be drawn.

For the purpose of interrupting a power arc drawn between the contacts,an arc extinguishing structure or arc chute, generally indicated at I2is provided to receive the arc. Generally such a circuit breakercomprises a plurality of arc chutes, one for each phase conductor of thepower circuit to be controlled. It will be understood that our inventionis equally applicable to a single phase or polyphase circuit breaker. Asis illustrated in the drawings, the arc chute I2 is of the so-calleddown draft type such as is disclosed in Linde Patent 2,335,068, referredto above. By down draft type is meant that the arc gases from the arcchute are discharged downwardly. It should be understood, however, thatour invention is also applicable to circuit breakers which are not ofthe down draft type,

closed in the above-mentioned4 Linden Patent 2,335,068. The electriccircuit breaker illustrated comprises a main supporting frame or unit Ifor the relatively movablecontact structure which comprises relativelyiixed current carrying consuch, for example, as circuit breakers,wherein the gases from the arc chutes are discharged laterally as inLinde Patent 2,293,513.

The arc chute I2 of our circuit breaker is preferably constructed inaccordance with the arc shield disclosed and claimed in Boehne Patent2,270,723, granted January 20, 1942, and assigned to the same assigneeas the present application. Preferably, the arc extinguishing structureor-arc chute I2 comprises spaced side walls I3 and Il composed of arcresisting material such as an asbestos cement compound, each side wallhaving on the side facing the other wall a plurality of parallel fins,ridges or barriers I5, as best shown by Figs. 2 and 4. The ilns I5 areprei- Ierably integral with the side walls I3 and Il, which side wallsare preferably clamped together as by means of bolts IB with the ridgedor ilnned sides thereof adjacent to each other. The length and spacingor the fins or ridges I5 are such that when the sidewalls I3 and Il areclamped together the ilns are spaced and interleaved with respect toeach other, that is, in staggered relation so as to form a. s'inuous orzigzag passage i1 into which the arc is driven from the entrance portioni8 of arc chute I2 which is best shown in Fi 4.

eferring more particularly to Fig. 4, there is illustrated a transversesection of the zigzag arc passage I1 defined by interleaving fins orridges I8. 'I'he fins or ridges i5 are shown as tapering towards theentrance I8 of the arc chute I2. It will be observed that this taperedportion of the uns causes thearc passage I1 to be more and morerestricted as the arc approaches the exhaust portion of the chute.

Preferably th'e chute sides I8 and I8 are molded with the ridges or finsI8 integrally formed therewith and -any recesses, raised portions or thelike are formed during the molding process. To save the expense of twoseparate molds, our chute sides I8 and I8 may be molded as identicalpieces from a single mold. Fig. 3 shows how the chute sides I8 and I8may be molded as identical pieces, the dotted portions I8 and 28 beinginitially included in the molded chute sides I8 and i8, respectively.I'he dotted portion i8 of chute side I8 is cut away and correspondinglythe dotted portion 28 of ch'ute side I8 is cut away so that the chutesides are defined by the solid lines of Fig. 3. The fins of the chutesare arranged so as to be unsymmetrical about a central arc dividingmember 2i associated with each chute side whereupon interleaving of theribs or fins I8 will result upon assembly of the chute sides initiallymolded identical in shape.

As initially molded and clearly evident from Figi. 3. each chute side I8and I8 is provided with L-shaped recesses 22 and 28, with the base ofthe L-shaped recesses 22 and 28 pointing towards each other. Each chuteside I8 and I8 is also provided with a pair of curved arcing hornrecesses 28 and 25 which are of similar shape. recess 28 being invertedrelative to recess 28. By cutting away portion I8 of chute side I8,indicated in dotted lines in Fig. 3, a portion of each of the recesses22 and 28 is cut away. Byfcutting away portion 28 of chute side I8,indicated in dotted lines in Fig. 3, a portion of each of the recesses28 and 28 is cut away. y

The lower end of -arc chute I2 is the exhaust end of the arc chute. Inorder to cool the arc gases properly before being exhausted from thechute a pluralityvof parallel arranged cooling plates 28 are provided.These cooling plates 28 are very similar to the cooling plates providedin the above-mentioned Linde patentsl for cooling the arc gases and arepreferably formed of copper or other good thermal conducting material.These cooling plates are inserted in notches 21 preferably molded in thech'ute sides I8 and I8.

The construction of the contacts of the circuit breaker form no part'ofour invention. Preferably, however, movable arcing contact l supportedon pivotally mounted arm 8 moves through the entrance portion I8 of arcchute I2. As illustrated. movable arcing contact 8 moves closelyadjacent to an arcing horn 28 supported in recesses 28 and 28 of chutesides I8 and I8, respectively, the edges of arcing horn 29 beingdisposed In the cooperating recesses 28 and 28. Arcing horn 28 isprovided with an extension 88 which includes `the opening 8l so thatarcing horn 28 may be electrically connected, as by a bolt passingthrough opening 8i to one side of the associated electric circuit. Anarcing horn 82 adapted to be 4 electric circuit is positioned incooperating recesses 2l and 28 of chute sides I8 and i8, respectively.-Arcing horn 82 is electrically connected to a blowout coil 88 mountedon a core 88 and separated from the coil by an insulating cylinder 88.The core 88 of the blowout coil 88 is adapted to extend through drilledopenings such as 88 in the chute sides I8 and I8 so as to abut magneticplates 81, one associated with each' chute side I8 and I8. A suitablebolt 88 passing through the chute sides, plates 81 and an opening incore 88 holds the core 88 and magnetic plates 81 together so as toproduce a strong magnetic field for mov- Raised portion 88 cooperateswith a notched-out portion 88 in the magnetic plates 81.

One end of magnetic blowout coil 88 is connected to arcing horn 82. asis indicated at 8|.

` The other end of magnetic blowout coil 88, as is indicated at 82, isconnected to a conducting supporting member 88 which is a bar-like piecebent across its width into a generally U-shaped conguration the lowerportion oi' which matches the cooperating recesses 28 and 22 formed inchute sides I8 and I8, respectively. When the chute sides I8 and i8 arebolted together, as indicated in Figs. 2 and 8, the lower portion whichincludes leg 88 of the U-shaped member 88 is held with its edgeseffectively keyed into the L-shaped recesses 28 and 22 in chute sides I8and I8, respectively. Accordingly the arc chute I8 may be supportedfirmly and reliably from the upper leg of the U-shaped member 88 for itwill vbe apparent that the support 88 cannot be displaced from its keyedposition in the assembled are chute until the 'two sides are unboltedand separated from one another.

It will be discerned that the are chute supporting member 88 derives'itstenacity with respect to the are chute from the fact that the main bodyportion of the member is provided with an effective anchorage aifordedby'the projecting or offset portionV 88 and the corresponding grooves orrecesses provided in the chute sides for snugly receiving therein theedges of the main body and oil'set portions of the supporting member.

Preferably, conducting supporting member 88 is fastened by means of asingle cap screw 8l to an extension 88 of the stationary contactstrueture which is electrically connected to the bottomof conductorstud8.

In orderto support the other side of the arc chute I2, we provide afabricated supporting member 81 comprising two vertically extendingpieces 88 identical in configuration. Joined together at the top by aU-shaped crossover member 88. The lower ends of the vertical members 88making up fabricated supporting member 81 are provided with an openended disengaging slot 88. A single cap screw 8i passing through thebight of U-shaped member 88 of supporting member 81 holds the fabricatedsupport 81 to the contact block supported from conductor stud 8. Theopen ended disengaging slots 88 are adapted to cooperate with a bolt 82passing through are chute I2 and through the opening 8| in arcing h'orn28. It will be obvious that with the above construction theare chute I2can readily be removed merely by removing the cap screw 88 and looseningthe boit 82 after which the arc associated with the other side of said'I8 chute I2 may be slid to the left, as viewed in Fig. 1, whereby boltl2 becomes freed from the disensaglng slots Il. v

From the above discussion, it will be obvious that the cooperatingrecesses 23 and 22 of chute sides I3 and Il, respectively, provide avery simple means for securely ailixing the arc chute supporting memberI3 into the ch'ute structure without the requirement of any additionalfastening means whatsoever and furthermore with this construction a veryeasily removable arc chute is obtained. Moreover, it will be observedthat during the interrupting operation, that is, after the movablecontacts 4 and 5 have separated from the coacting stationarycontacts 2and 3 respectively, the upper portion of supporting member 43 furthercooperates in that it serves as a shunt path around the fixed contactsthrough which current flows for energizing the blowout coil coincidentalwith the transfer of the arc root from the fixed arcing contact 3 to thearc runner 32.

While we have shown and described a particular embodiment of ourinvention, it will be obvious to those skilled 'in lthe art that variouschanges and modiilcations may be made without departing from ourinvention in its broader aspects and we, therefore, aim in the appendedcla-ims to cover all such changes and modifications as fall within thetrue spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. In an electric circuit breaker, supporting structure, an arc chuteconstructed of complement-ary parts, grooves in adjacent surfaces otsaid complementary parts, said grooves having one portion thereofangularly disposed with respect to another portion thereof, a supportingmember having-a portion thereof adapted to project outwardly from saidarc chute and another portion thereof having an oil'set portion andbeing adapted to flt within the grooves in the complementary parts ofsaid arc chute. whereby said supporting member is secured in positionwith re- -spect to said arc chute, and means cooperating with theportion oi' said supporting member which projects outwardly from saidarc chute for securing said supporting member to said supportingstructure.

2. In an electric circuit breaker, supporting structure, an arc chuteconstructed of complementary parts, grooves in adjacent surfaces of saidcomplementary parts, said grooves having one portion thereof angularlydisposed with respect to another portion thereof, a supporting memberhaving a portion thereof adapted to prolect outwardly from said arcchute and another portion thereof having an offset portion and beingadapted to fit within the grooves in the complementary parts of said arcchute, whereby said sup- Porting member is secured in position withrespect to said arc chute, means cooperating with the portion of saidsupporting member which projects outwardly from said arc chute 'forsecuring said supporting member to said supporting structure, asupporting arm secured to said supporting structure, and means forsecuring said arc chute to said supporting arm.

3. In an electric circuit breaker, supporting structure, an arc chute, asupporting member secured to said arc chute and having an outwardlyprojecting portion, means for removably securing the outwardlyprojecting portion of said supporting member to said supportingstructure,- a supporting arm secured at one end thereof to saidsupporting structure, a slot in the other end of said arm, and means onsaid arc chute for removably connecting said arc chute to saidsupporting arm byv a sliding engagement with said slot.

BENJAMIN E. SPIRO. RALPH J. BASKERVILLE.

REFERENCES CITED The following references are oi"record in the ille ofthis patent:

UNITED STATES PATENTS Number Name Date 40 `1,398,981 Tritle Dec. 6, 19211,804,729 Wilms et al. May 12, 1931 1,914,129 Jennings June 13, 19331,955,961 Jackson Apr. 24, 1934 2,020,935 -Ellis et al Nov. 12, 1935 452,098,578 Hammerly Nov, 9, 1937 2,270,723 -Boehne Jan. 20, 19422,335,068 Linde Nov. 23, 1943 2,349,881 Slepian May 23, 1944

